Glucose utilization indices (GUI) of interscapular brown adipose tissue (IBAT) declined by 84% after 48 h starvation. Two-thirds of the overall response was observed within 6 h, correlating with decreased insulin concentrations. Re-feeding 48 h-starved rats restored insulin concentrations and evoked a rapid 15-fold increase in IBAT GUI. GUI values after re-feeding were markedly higher than those observed at equivalent insulin concentrations in control post-absorptive rats.
